Thanks for your bug report. I am not aware of any recent reports of $readini causing mIRC to crash. Can you provide a link to the bug report that you are referring to? I have tested $readini and it is returning data from ini files as expected. For example:

test {
  var %fn = test.ini

  writeini %fn a a2 a3
  writeini %fn b b2 b3
  writeini %fn c c2 c3

  var %item = $readini(%fn,a,a2)
  echo item: %item
  var %item = $readini(%fn,b,b2)
  echo item: %item
  var %item = $readini(%fn,c,c2)
  echo item: %item